#include <fstream>
#include <string.h>
using namespace std;

char cuv[2000000];

int main()
{
	ifstream in("text.in"); ofstream out("text.out");
	int nrcuv=0, nrlit=0, i;
	while (in>>cuv)
	{
		bool lit = false;
		for (i=0;i<strlen(cuv);i++)
			if (cuv[i] >= 'a' && cuv[i] <= 'z' || cuv[i] >= 'A' && cuv[i] <= 'Z')
			{
				nrlit++;
				if (lit == false)
				{
					lit = true;
					nrcuv++;
				}
			}
			else lit = false;
	}
	out<<nrlit/nrcuv;
	return 0;
}